Alexandrite
Chrysoberyl
Chrysoberyl is a beryllium-aluminum oxide mineral with a chemical composition of BeAl2O4. It is distinctly different from the beryllium-aluminum silicate (Be3Al2(SiO3)6 mineral known as "beryl," although the similar names can cause confusion. Chrysoberyl is best known for its use as a gem. There are multiple varieties of gem chrysoberyl, each with its own name and unique physical properties.Ordinary chrysoberyl is a yellow to yellow-green to green gemstone with a translucent to transparent diaphaneity. Transparent specimens are usually cut into faceted stones. Specimens that are translucent or with silk are usually cut into cabochons. A photo of ordinary chrysoberyl is shown at the top of this page. The name chrysoberyl comes from the Greek words chrysos, meaning golden, and beryllos, which refers to its beryllium content. Chrysoberyl has been a prized stone for thousands of years in Asia, as it is believed to provide the wearer with protection from the evil eye. There are three different gem varieties of chrysoberyl. Each of these stones is chemically alike, but optically very different, each one having a unique and beautiful feature of its own. The pale yellow green variety of chrysoberyl came from Brazil, and was known as chrysolite. Today however, the most popular varieties of chrysoberyl are cat’s eye and alexandrite. Alexandrite, which is a very durable and rare stone, displays a beautiful color change. In the daylight, it is green, but under incandescent light, it changes to a red, mauve, or brown color. It has been said that alexandrite was named after czar Alexander II, as it was discovered on the czar’s birthday in 1830, in the Ural Mountains.
Alexandrite
“Emerald by day, ruby by night,”
![](https://cdn.shopify.com/s/files/1/2436/0515/files/alex_480x480.png?v=1629535433)
Alexandrite |
|
Variety of |
Chrysoberyl |
Crystallography |
Orthorhombic |
Colors |
Varies in color with incident light: green, blue-green, or pale green in daylight; mauve, violet to red, purplish in incandescent light. |
Luster |
Vitreous |
Hardness |
8.5 |
Birthstone |
June |
Etymology |
Named after Czar Alexander II of Russia. |
Origins |
Ural Mountain, Brazil, Sri Lanka, Burma, Madagascar, Tanzania. |
Formula |
BeAl2O4 + Cr |